Influence of Meso-Structure Parameters on Wave Propagation in Soil-Rock Mixture

Abstract

The macro mechanical properties of soil-rock mixture are closely related to the meso-structure features of block stones, namely, content, size, and shape. To promote the engineering application of soil-rock mixture, it is important to explore the meso-structure of the mixture, and evaluate its constitutive properties. The previous studies have shown that the wave propagation in the mixture is highly sensitive to the rock content and compaction. To clarify the meso-structure features of soil-rock mixture, this paper establishes a discrete element model of the mixture based on Particle Flow Code (PFC), investigates the wave propagation features in the model with different meso-structure parameters, and analyzes how the meso-structure parameters affect the wave propagation. The results show that: With the growing rock content, the first wave amplitude increased, while the take-off time shortened; With the growing feature size of block stone, the first wave amplitude gradually decreased, while the take-off time gradually lengthened; The soil-rock mixture containing spherical block stones had the highest first wave amplitude and shortest take-off time, while the mixture containing rectangular block stones had the lowest first wave amplitude and longest take-off time. With the growing rock content, the maximum amplitude, dominant frequency, and spectral area all exhibited an increasing trend; With the growing feature size of block stone, the maximum amplitude, dominant frequency, and spectral area all exhibited a decreasing trend.

Effect of Moisture Distribution on Velocity and Waveform of Ultrasonic-Wave Propagation in Mortar

“…Therefore, the propagation properties of ultrasonic waves can be used to estimate the internal state of the target material, and this method is attracting attention as an effective method for measuring internal defects in the field of concrete inspection [ 18 , 19 , 20 ]. However, concrete is an inhomogeneous material, which contains several voids, cracks, and coarse aggregates, and its density distribution is nonuniform [ 21 , 22 ]. In addition, ultrasonic waves propagate in a complicated pattern due to reflection, confusion, diffraction, interference, etc., when they approach discontinuities [ 23 ].…”